Tendu leaves refuse as a biosorbent for COD removal from molasses fermentation based bulk drug industry effluent

Abstract

Physico-chemical properties of effluent from a molasses fermentation based bulk drug unit were analyzed and found to be typical of the effluent from molasses fermentation except for high amount of phenols. The Chemical Oxygen Demand (COD) removal capacity of tendu (Diospyros melanoxylon) leaves refuse of bidi industry and its comparison with Granulated Activated Carbon (GAC) has been presented. Batch kinetics and isotherm studies were studied under varying experimental conditions of contact time, COD concentration, adsorbent dose and pH. Maximum COD removal was observed at a narrow pH range between 7 and 8. The kinetic data were best fitted to the pseudo-second-order chemisorption model. The adsorption followed both Langmuir and Freundlich isotherms. As per Langmuir model, maximum adsorption capacity was found to be 48.54 mg and 154.8 mg COD per g for tendu leaves refuse and GAC, respectively. The results illustrate how tendu leaves refuse, a solid waste disposal menace from bidi industry, is effective biosorbent for the removal of COD; offering a cheap option for primary treatment of the effluent. @JASEM

Reduction of COD in water-based paint wastewater using three types of activated carbon

“…These constants also determine the adsorption capacity of organic pollutants and the extent of COD reduction by adsorbents [13]. The larger the value of K f and the smaller the value of 1/n, the more effective the adsorbent is for adsorption and the higher the adsorption capacity and, in this case, the easy uptake of COD from wastewater [32,38]. Devi [13] reported that 1/n was dependent on the order of reduction in COD concentrations with the adsorbent dose while K f was dependent upon the extent of COD removal by the adsorbents.…”

“…Furthermore, values of 1/n ranging between (0 < 1/n < 1) were considered as a measure of the adsorption intensity or surface heterogeneity, as the system becomes more heterogeneous in nature, the value of 1/n gets closer to zero [10,16,32,41]. The magnitude of n, on the other hand, was reported to give an indication of the favorability of adsorption [16,32,41] and the higher the n signifies that the biosorbent surface was heterogeneous in nature and was high enough for effective separation [38]. More specifically, n values ranging between 2-10 represent good, 1-2 moderately difficult and less than 1 denote poor adsorption characteristics of the adsorbent [16,32,41].…”

“…Adsorption isotherms describe how the adsorbate interacts with the adsorbent and the relationship between the amount adsorbed by a unit weight of solid sorbent and the amount of solute remaining in the solution at equilibrium [36][37][38][39]. The Freundlich and Langmuir isotherm equations have been extensively to represent the equilibrium adsorption data obtained from activated carbon-organic contaminant systems [32].…”

“…The Langmuir constant b reflects quantitatively the affinity between the adsorbent and adsorbate and the higher the value obtained, the higher the affinity for COD adsorption onto the adsorbent material [32]. Moreover, of the essential characteristics of the Langmuir isotherm is the dimensionless constant separation factor for equilibrium parameter, R L, which is defined as [38,43]:…”

Treatment of pulp and paper mill effluent using low cost adsorbents: An overview

“…Effect of adsorbent dose: The three activated carbons differ significantly in their COD capacity. This decrease in COD uptake capacity with increase in dose of activated carbon may be due to the formation of clusters of carbon particles resulting in decreased surface area (Nagda, 2006). At low concentration, the interaction between solute and solvent increase, so the solute has low tendency towards activated carbon and high affinity towards solvent (Nadeem et al, 2006).…”